The present invention relates to the art of manufacture and pertains particularly to method and apparatus for the sizing of cylindrical bores.
Many machines and articles of manufacture includes the use of cylindrical pins or shafts tight fitting into cylindrical bores. Such pins are normally press fitted into the bores and are required to maintain their position in the bore under considerable stress.
In order to insure proper fitting of such pins and bores, it is necessary to maintain fairly precise tolerances between the pin and bore. Tolerances are difficult to maintain without the use of numerous expensive operations. For example, bores may be formed by drilling and then bored or machined to a predetermined diameter. As the boring tool wears, the hole or bore becomes smaller. This may require another machining operation in order to obtain the proper size bore. One of the problems of such machining operations is that they are expensive. Another problem with such operations is that, as a finer cut is taken to more precisely size the bore, the finish within the bore becomes very smooth. Such finishes are undesirable when the walls of the bore are required to hold a pin or the like in place therein.
One approach to the problem of sizing bores, is disclosed in U.S. Pat. No. 3,691,805. The problem with such approach, however, is that the bore within the work piece becomes highly finished; and thus, incapable of tightly gripping and retaining a pin extended therein.